In many industries, in particular in oil production, the determination of multiphase fluid (e.g., oil/water/gas) composition and flow are important for determining how much fluid of any given phase is generated in a reservoir and is being pumped out or transported through pipes. There are many commercial instruments currently used that can provide this information, but since no one device can make all the required measurements, separate instruments of different types from multiple manufacturers are typically required to provide a complete answer. For example, one instrument may measure fluid flow, whereas another one measures the fluid composition.
Often these instruments have severe constraints and limited range of operation. For example, capacitance probes for measuring oil/water composition do not work well when the fluid becomes water continuous. Coriolis flowmeters are mass flowmeters that can also be operated as vibrating tube densitometers. The density of each phase may be used to convert the mass flow rate for a particular phase into a volumetric measurement. Numerous difficulties exist in using a Coriolis flowmeter to identify the respective mass percentages of oil, gas, and water in a total combined flow stream, particularly when there is gas present in the liquid.
Additionally, most of the fluid property measuring instruments require the flow to be diverted out of a principal flow pipe and into that particular instrument. Others require physical contact between the sensor and the fluid, which require a lot of maintenance for caustic fluids. The present invention allows measurements of multiple parameters of a multiphase system using noninvasive techniques where the sensors are attached on the outside of an existing pipe or on a small spool that is inserted in the line and all the sensors are acoustics based except the temperature sensor.